In line heat exchanger with bypass



April 22, 1969 u. R. JAEGER 3,439,739

IN LINE HEAT EXCHANGER WITH BYPASS Filed Feb. 8, 1967 INVENTOR. ULR/C R. JAEGER BY 7 M ATTORNEY United States Patent US. Cl. 165164 8 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a heat exchanger comprising substantially concentric members having a plurality of inner tubes bonded to a body of pervious metal material wherein the heat exchanger surfaces are in contact with a first and second heat exchange medium.

Summary of the invention The heat exchange apparatus comprises first and second conduit means and a third conduit positioned within the second conduit means with a pervious body of metal particles surrounding the third conduit means within the second conduit means and bonded to the third conduit means so as to enhance heat transfer. The apparatus is provided with inlets and outlets on the shell so as to direct heat exchange fluid normal to the flow of the heat exchange medium passing through the first and second conduit means.

It is an object of this invention to provide a heat exchanger which is highly compact and yet capable of high efficiency and low pressure drop.

Other objects of the invention will be apparent from the following description of the invention.

FIGURE 1 is an isometric-schematic of the heat exchanger of the present invention.

FIGURE 2 is an axial cross-section along the lines 22 oin FIGURE 1.

FIGURE 3 is a longitudinal cross-section along the lines 3-3 of FIGURE 2.

In one embodiment of the present invention, the heat exchanger 1 comprises an outer tube or conduit 10. Located within this tube or conduit is an interior heat exchange unit 11. This interior heat exchange unit 11 comprises a second tube or conduit 12. Located within this conduit 12 is a pervious body 13. Located within this pervious body 13 is at least one third tube or conduit member 14. Preferably, a plurality of such members 14 are located within the pervious body 13. As can be seen from FIGURES 1 and 3, the interior heat exchange member also has plate members 15 and 16 on opposite portions of the pervious body, through which the tube members 14 pass with appropriate sealing means. The conduit member 12 of the inner heat exchange member 11 has openings 17 and 18 preferably flanged and threaded as shown in FIGURES 2 and 3. Between the pervious body 13 and the conduit 12 there are void spaces 27 and 28.

The interior heat exchanger 11 is preferably constructed separately.

As will be understood, various combinations of metals may be utilized in forming the inner heat exchanger 11. The solid portions and the pervious body may be of the same metal or alloy, or the pervious structure and the solid member may be composed of different compositions. For example, both the pervious body and solid portions may be formed of the same stainless steels, coppers, brass, carbon steels, aluminurns or various combinations thereof. As will be evident, the ultimate use of the resultant 3,439,739 Patented Apr. 22, 1969 structure determines the specific combination of alloys to be employed.

The production of the pervious body 13 is most flexible; for example, it may be produced by a process wherein particles, usually spherical, are poured by gravity into an appropriately shaped confined space and usually vibrated to cause the particles to compact uniformly. As is obvious, the choice of particle size will largely determine the size of openings in the resulting pervious body. The body of particles so packed is then treated in accordance with any of the well known metallurgy practices--e.g., sintering, welding; brazing or soldering employing an appropriate coatingto produce a metallic bond between the particles. Thus, there is provided a pervious body whose bulk density, or apparent density, is but a fraction of the density of the metal or alloy from which the particles are obtained. Furthermore, such process results in a metallic bond between the perivous body and solid material around and within the body.

While the above described process is preferred in the instant invention, other processes may be employed. For example, it is possible to blend intimately a particulate material with either a combustible substance or a soluble material whose melting point exceeds the sintered temperature of the particulate material. After the blend is compacted and treated to achieve a metallic bond, the combustible substance may be burned away or the soluble material removed by leaching or dissolving with a liquid.

A still further method of producing the pervious body comprises melting a metal or alloy and casting it into the interstices of a loose aggregate of a particulate soluble material whose melting point exceeds that of the metal, preferably having a specific gravity of the molten metal. Upon solidification of the metal, a component is produced which contains the network of the soluble material interspersed within the solid metal Which soluble material is thereupon removed by leaching or dissolving, leaving behind it interstices that interconnect and form a pervious network within the resultant metal body.

A still further method of producing such pervious bodies comprises weaving or knitting metal wire into a mesh arranged in a plurality of layers. According to this process, a control of porosity is obtained by appropriate choice of wire diameters and openings arranged between adjoining wires as well as the juxtapositioning of superimposed layers of the woven or knit mesh.

Any desired shape of inner heat exchanger may be provided, with the inner tubes 14 and pervious body 13 shaped accordingly to fit. Furthermore, the tubes 14 may be of any desired cross-section, but they are showfi in the drawing as having a substantially elliptical crosssection.

Considering now the method by which the inner heat exchanger may be produced, it will be evident that the pervious body 13 may be formed about the tubes 14 in any of the methods indicated hereinbefore. The tubes 14 may be positioned in the apertures of end plates 15 and 16, and the resulting assembly situated in an appropriate mold. Thereafter, the particles of pervious body may be poured into the mold, with provision having been made for leaving voids 27 and 28. Following any of the metallurgical processes indicated hereinbefore, a metallic bond may be created between the tubes and the particles of the pervious body, as well as between each of the particles of the previous body. The assembly may then be inspected, and the openings of header plates 15 and 16 through which the tubes pass may be appropriately sealed if such a seal has not been accomplished by the preliminary joining process. The header plates may then be suitably secured within tube 12 and appropriately sealed.

3 The openings \17 and 18 may then be threaded on the inside.

Alternatively, the tubes 14 may be positioned within the header plates 15 and 16, the resulting assembly situated within the tube 12, and supported by an appropirate mold. Portions of one of the header plates may be apertured so that the particles of pervious body may be inserted therethrough and a channel core may be provided. The resulting assembly may then be treated in accordance with any of the foregoing methods to simultaneously create a metallic bond (A) among the particles of the pervious body, (B) between the tubes 14 and the header plates 15 and 16, (C) between the pervious body and each of the tubes 14, (D) between the pervious body 13 and the header plates 15 and 16, and (E) between the header plates 15 and 16 and the inner periphery of tube 12. Following such treatment, the apertures of the header plates through which the particles of pervious material 13 and core were introduced may be resealed. As in the first method of manufacture, the fittings 17 and 18 are then preferably threaded on the inside.

The outer conduit member also has openings 19 and 20 which are preferably flanged and threaded as shown in FIGURES 2 and 3.

One or more of the inner heat exchange members 11 are inserted into the outer conduit member 10. The number of openings 17 and 18 in the inner heat exchange member will correspond with the number of openings such as 19 and 20 in the outer heat exchange member. Obviously, if there is a difference in the number of openings, the additional openings can be blocked off so that the number of operative openings is the same in both members 11 and 10.

Corresponding openings in the inner heat exchange member 11 are lined up with corresponding openings in the outer conduit 10. A fourth conduit member 21, also preferably threaded as at 22, is then screwed, or otherwise operatively connected through the openings 19 and 17, to the inner conduit 12. Likewise, a fifth conduit member 23, preferably having threads 24, is operatively connected to the openings 18 and 20 to the conduit 12. To insure a tight fit, nuts 25 and 26 may then be screwed in place to hold the members 21 and 23 in operative relationship with the conduit 12. Obviously, suitable fittings may be connected to conduits 21 and 23, and to opposite ends of conduit 10 for connection of appropriate piping, both which can in turn be connected to means for circulating a heat exchange medium, such as a pump.

Obviously, other types of connections and sealing arrangements may be made between the conduit means 21 and 23 and the inner conduit 12, and between the conduit means 21 and 23 and the outer conduit 10.

As was seen previously in the construction of the inner heat exchange member 11, void spaces 27 and 28 exist between the second tubular member 12 and pervious body 13. Additionally, after the irmer heat exchange member 11 has been inserted into the outer conduit member 10, there exist void spaces 29, 30, 31 and 32 between the outer conduit member 10 and the inner heat exchange member 11. As shown in FIGURE 3, there are also void spaces 33 and 34 within the conduit 10 on either side of the plates and 16, respectively.

It also will be observed that the second conduit member 12 has an outer surface 12(a) as shown in FIGURE 3 in communication with the void spaces 29 and 30, and an inner surface 12(b) which is in communication with the void spaces 27 and 28. Similarly, the plates 15 and 16 have, respectively, outer surfaces 15(a) and 16(a) which are in communication with, respectively, the void spaces 33 and 34. The plates 15 and 16 also have inner surfaces 15(b) and 16(b) which are, respectively, in communication with the void spaces 27 and 28. The conduits 21 and 23 have outer surfaces 21(a) and 23(a) which are in communication with void spaces 29 and 30, respectively, while the inner surfaces 21(b) and 23(1)) 4 are, respectively, in communication with the void spaces 39 and 40 inside of conduits 21 and 23.

In the operation of the heat exchanger of the present invention, as shown by the arrows 35 and 36, a first heat exchange medium, which may be a liquid, for example oil, is introduced into the conduit 21 and into void space 39 and is thus in heat exchange relation with its inner surface 21(b). It passes through the outer conduit 10, through the second conduit 12 and into the void space 27 Where it is in heat exchange relation with the inner surface 12(b) of the conduit 12. There it distributes itself substantially evenly and flows downwardly through, and is in heat exchange relation with the porous body 13. It is collected in the void space 28 where it is again in heat exchange relation with the inner surface 12(b) of conduit 12. It then passes out through void space 40 of conduit 23 where it is in heat exchange relation with the inner surface 23(b).

As shown, for instance, by the arrows 37 and 38, a second heat exchange medium which also may be a liquid, for example water, which is at a lower temperature than the first heat exchange medium, is circulated through the outer conduit '10. As shown in FIGURE 3, as the second heat exchange medium approaches the inner heat exchange member 11, it -will be located in the void space 34. As it approaches the inner heat exchange member 11, as shown by the arrow 37 (a), a portion of the second heat exchange medium will pass through the tubes 14 and will there be in heat exchange relation with the tubes 14 and pervious body 13. It will then pass out at the opposite end of the inner heat exchange member 11 and into the large void 33 in conduit 10, where a portion thereof will be in heat exchange relation with the outer surface 15(a) of plate 15.

A second portion of the second heat exchange medium however, as shown by the arrows 37-(b) in FIGURE 3, will pass into the voids 29, 30, 31 and 32, and a portion of the second portion will be in heat exchange relation with the outer surface 16(a) of plate 16. The second portion of the second heat exchange medium will also be in heat exchange relation with the outer surface 12 (a) of the second conduit member 12 and the outer surfaces 21(a) and 23(a) of the fourth and fifth conduit members 21 and 23. A short distance after the second heat exchange medium passes the plate 15, it will rejoin that portion of the second heat exchange medium which passes through the tubes 14. To some extent, the second portion of the second heat exchange medium will be in heat exchange relation with the outer surface 15(a) of the plates 15 in this region.

It will thus be seen that the first heat exchange medium will be in heat exchange relation with the second heat exchange medium as the first heat exchange medium passes through the void 39 of conduit 21. Heat will flow from the first heat exchange medium to the inner surface 21(b), to the outer surface 21(a) and then into the second heat exchange medium as it passes through void 29.

As the first heat exchange medium passes into the void space 27, heat will flow to the inner surface 12(b) to the outer surface 12(a) and then into the second heat exchange medium in void 29.

Some heat will also flow from the first heat exchange medium in the void 27 to the inner surface 16(b) to the outer surface 16(a) into the second heat exchange medium in the void 33. Likewise, some will flow to the inner surface 15(b), outer surface 15(a), and thence to the second heat exchange medium in void 34.

As the first heat exchange medium passes through the porous body 13, heat will flow from the first heat exchange medium into the porous body 13, into the tubes 14 and thence into the second heat exchange medium.

Additionally, as to that portion of the first heat exchange medium which passes through the outer portions of the previous body, marked 13 (a) in FIGURE 2, there will be heat flow from the first heat exchange medium into the pervious body 13 (a), to the inner surface 12(b) of conduit 12, to the outer surface 12(a) and then into the second heat exchange medium as it passes through the void spaces 31 and 32 shown in FIGURE 2.

When the first heat exchange medium collects in the void space 28, there will again be heat flow from the first heat exchange medium to the inner surface 12(b) of conduit 12, to the outer surface 12(a) and then into the first heat exchange medium located in void 30'. Also, heat will flow from the first heat exchange medium to surfaces 15(1)) and 16(b), to the surfaces 15(a) and 16(a), and then into the second heat exchange medium in the voids 33 and 34, respectively.

As the first heat exchange medium passes out through the void space 40 of the conduit 23, there will be heat exchange from the first heat exchange medium to the inner surface 23(1)), to the outer surface 23(a) and then to the second heat exchange medium, which is in the void space 30.

It is thus seen that the heat exchanger construction of the present invention provides a very large number of surfaces for heat exchange and thereby results in efficient and efiective heat exchange with low pressure drop. The size and contour of the void spaces 29, 30, 31 and 32 determines the relative proportion of the volume of second heat exchange medium which passes between the conduits 10 and 12 in comparison to through the tubes 14. The greater the volume which passes between the conduits 10 and 12, the lower will be the pressure drop.

The outer conduit 10 may be made of any convenient material such as metal of rubber, since there are no heat conductivity requirements in regard to this member. However, the tubular members 12 and 14 must be made of a material having good heat conductivity, and, for this reason, materials such as copper and aluminum and their alloys are preferred. Conduits 21 and 23, while being less critical in regard to heat conductivity than tubular members 12 and 14, are nonetheless preferably also made of good heat conductivity material such as copper and aluminum if the absolute maximum amount of heat transfer is desired. However, they could also be made of rubber at a slight sacrifice to heat exchange efficiency.

Additionally, corrosion problems must be considered. Thus, the material to be used for these parts of the heat exchangers will be dictated by the heat exchange mediums to be circulated. This naturally suggests the use of such materials as stainless steel as well as corrosion resistant alloys of copper and aluminum. The particular materials to be used for these parts of the heat exchanger may be readily determined by those skilled in the art, in accordance with the particular corrosion problems to which the heat exchanger is to be applied.

Obviously, there can be one or a multitude of inner heat exchange members 11 in the conduit 10. More than one can be placed at a given cross section of the tube 10 if the tube 10 is made of large enough cross sections with appropriate openings 18 and 19 for additional conduits 21 and 23. Alternatively, there need only be one set of openings 18 and 19 and a header and manifold used to distribute and collect the first heat exchange medium to the various inner heat exchange members 11 within the conduit 10. Such modifications will be readily apparent to those skilled in the art.

It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modifications of form, size, arrangement of parts and detail of operation. The invention rather is intended to encompass all such modifications which are within the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. A heat exchange apparatus which comprises:

(A) a first conduit means for passage of a first heat exchange medium,

(B) a second conduit means for passage of a second heat exchange medium, said second conduit means having a first inlet and a first outlet and said second conduit means positioned within said first conduit means defining a substantially annular passageway within said first conduit means, said second conduit means further having a pervious body positioned therein,

(C) a third conduit means for passage of said first heat exchange medium, said third conduit means positioned within said pervious body within said second conduit means and in communication with said first conduit means,

(D) a second inlet and a second outlet communicating with said first conduit means whereby the first heat exchange medium concurrently passes through said first and said third conduit means, and

(B) said pervious body being in heat exchange relationship between said second and third conduit means and in communication with said first inlet and said first outlet.

2. A heat exchange apparatus according to claim 1 wherein said first conduit means is made of a flexible material.

3. A heat exchange apparatus according to claim 2 in which said first conduit means is made of rubber.

4. A heat exchange apparatus according to claim 1 in which said first conduit means is made of metal.

5. A heat exchange apparatus according to claim 1 in which said second conduit means and said third conduit means are made of a high heat conductivity material.

6. A heat exchange apparatus according to claim 5 in which corrosion resistance material is used for said second conduit means and said third conduit means.

7. A heat exchange apparatus according to claim 5 in which said firs-t inlet and said first outlet are also made of a high heat conductivity material.

8. A heat exchange apparatus according to claim 1 in which there are a plurality of said second conduit means.

References Cited UNITED STATES PATENTS 3,306,353 2/1967 Burne -164 3,289,756 12/ 1966 Jaeger 165-155 3,315,703 4/ 1967 Matthews et -al. 3,331,435 7/1967 Valyi.

MEYER PERLIN, Primary Examiner.

T HEOPHIL W. STREULE, Assistant Examiner. 

